OAKLAND — The peculiarity at O.co Coliseum Saturday night began a few minutes before first pitch. That was when Yankees first baseman Mark Teixeira, regularly battling aches and pains this season, was a late scratch due to tightness in his left rib cage. It continued in the middle of the fourth inning, when a group of lights mounted above left field suddenly went out, causing a 38-minute delay.

By the evening’s conclusion, the Yankees’ swagger-boosting trouncing of the Athletics, the American League’s premier club, Friday night was a distant memory. They left the Coliseum Saturday night losers for the first time in five games, failing to solve the stingy Scott Kazmir and falling 5-1.

The Yankees, down 2-1, were on the field warming up for the bottom of the fourth inning, when Athletics manager Bob Melvin emerged from the home dugout to alert the umpires what Yankees manager Joe Girardi had noticed in the second inning — a bank of lights overlooking left field was dormant.

The Yankees (35-32) then came off the diamond and the game was delayed at 8:19 pm local time. A circuit breaker outage was discovered and the breaker was reset manually in the left-field light tower.

Girardi was informed that the umpiring crew was ready to telephone the league’s headquarters in New York because the lights were not likely to turn on. The manager believed there was enough light to play on, but the night was not yet dark. Suspending the game and continuing it on Sunday as part of a doubleheader was a possibility.

But 38 minutes later, the game resumed after the lights, perched above a tarp-enclosed section of seats with commemorations to Reggie Jackson and Rickey Henderson, flickered and slowly ignited.

“It’s unfortunate,” Girardi said, “but it happens from time to time.”

Yankees starter Hiroki Kuroda had thrown warmup pitches when the delay was enforced. He played catch to keep loose during the stoppage and would not have taken the mound again had the interruption lasted another 10 to 15 minutes, according to Girardi.

But Kuroda (4-5, 4.32 ERA) resumed his outing and proceeded seamlessly, retiring the Athletics (41-27) in order with 16 pitches. The fifth inning was not as effortless. Eric Sogard initiated the frame with a walk. Coco Crisp then laid a bunt down the third-base line that a charging Kelly Johnson chose to field despite its path toward foul territory and the swift Crisp beat Johnson’s wild throw to first base comfortably.

A passed ball charged to catcher John Ryan Murphy advanced the runners and John Jaso’s groundout to first baseman Brian McCann, making his second career start at first base for the scratched Mark Teixeira, plated Sogard. A second passed ball then scored Crisp, doubling the Athletics’ lead with just a walk and an infield hit.

Kuroda got Josh Donaldson, recently considered a leading MVP candidate but mired in a miserable slump, to strikeout to extend the third baseman’s misery to 30 hitless at-bats. But Brandon Moss singled to center field to chase Kuroda.

“The runs I gave up in the fifth turned out to be a big moment tonight,” said Kuroda, who denied that the delay was a factor in his demise. “The fact that I couldn’t protect it was frustrating.”

Seeking a strikeout and without the services of the best strikeout-generating reliever in the majors, Dellin Betances, Girardi elected recently activated Shawn Kelley, the Yankees setup man before a back injury sidelined him for a month, to face the dangerous Yoenis Céspedes. Kelley accomplished the task by striking Céspedes out.

But Kelley did not come out for the sixth inning. Instead, it was David Huff, making his first appearance for the Yankees this season after the club acquired him for cash considerations from the Giants.

The left-hander struck out Jed Lowrie, but pinch-hitter Craig Gentry dropped a precise bunt, just beyond Huff’s reach and in front of second baseman Yangervis Solarte, for a single. Gentry immediately utilized his speed again, dashing home from first base on a double in the left-field corner by Andy Parrino.

The deficit proved insurmountable. And for six innings, Kazmir (8-2, 2.05 ERA) was the reason. The left-hander held the visitors to three hits over six innings. The run he surrendered was unearned. His earned-run average dropped to 2.05, second only to Yankees rookie sensation Masahiro Tanaka in the American League.

After producing 13 runs their previous two contests to snap a 12-game streak of four or fewer runs, the Yankees manufactured one run in the third inning and never crossed home plate again.

“He pitches,” Girardi said of Kazmir. “He lives on the edges. He changes speeds really well. We had a chance in the fifth to tie it up and when we didn’t, they came out in the bottom of the fifth and got two and that was the big swing.”

The Yankees’ chances to rattle Kazmir took a blow when Teixeira was ruled out. The first baseman said he woke up Saturday with tightness in the rib cage. The discomfort progressively worsened and peaked after he took full batting practice.

Fearful of risking another substantial for their top home run hitter, the Yankees chose to sit Teixeira, who is 12-for-23 (.522) with eight walks and a 1.545 on-base-plus-slugging percentage in 34 career plate appearances against Kazmir.

“He came in and said it was a little bit tighter and we decided it was probably best not play him,” Girardi said.

The Yankees are uncertain of the injury, but are hopeful Teixeira can play Sunday. Teixeira, who suffered an oblique injury in 2004, emphasized it was not an oblique issue. But his status for Sunday and beyond is unknown.